The present invention relates to an interline fishing rod in which an annularly or spirally shaped fishing line guide(s) is provided on and projected inwardly from the inside wall of a rod pipe.
In recent years, there has been used a fishing rod with a fishing line inserted and guided through the interior portion thereof because, with this type of fishing rod, a fishing line is difficult to be twined around the tip end of the fishing rod. In such interline fishing rod, since the fishing line is inserted through the interior portion of a rod pipe, generally, a fishing line guide is provided on the inner wall of the rod pipe in order to reduce the resistance of the fishing line. In connection with this structure for the interline fishing rod, there have been found various problems to be solved as follows:
(1) Since the joining portion of a fishing rod receives a load acting on a front side small diameter rod pipe which is joined with another rod pipe, the joining portion must have such a strength that can compete with the load. On the other hand, when a fishing line guide is provided in the interior portion of a large diameter rod pipe from the viewpoint of reduction of the resistance of a fishing line, a portion of the rod pipe including the fishing line guide is higher in rigidity than the other portions thereof in which such fishing line guide is not provided, and the centralization of stresses occurs in the portions having no fishing line guide. Especially, when the fishing line guide is so formed as to continue in a spiral shape, the rod pipe is lowered in strength in the neighboring portion of the portion where the fishing line guide is interrupted or terminated, and the stress centralization occurs in such lowered-strength portion of the rod pipe. In this manner, in a fishing rod, in general, the rigidity thereof varies according to the component portions thereof and, therefore, it is necessary to take measures to deal with the stress centralization. Also, if there is employed a swing-out joining system, then a forwardly arranged small diameter rod pipe must be structured in such a manner that it can be stored into the interior portion of a backwardly arranged large diameter rod pipe, which sets a limit on the dimensions of the respective component portions of the fishing rod. That is, the balance of the rigidity of the whole fishing rod must be set in compliance with such dimensional restrictions as well as in consideration of the stress centralization, so that the fishing rod can be flexed smoothly as a whole. PA0 (2) In Japanese Patent Publication No. 8-172980 of Heisei, in view of the fact that, if a fishing line guide is formed such that it has a circular section, then it will be contacted with a fishing line in a point contact manner, which impairs the durability of the fishing line guide and fishing line, there is disclosed an interline fishing rod, including fishing line guides which are formed in a spiral manner and each of which has a trapezoidal section. PA0 (3) There is provided an interline fishing rod in which a large number of fishing line guides, which are provided separately and are connected together continuously in an annular or spiral manner for guiding the fishing line, are provided on and projected from the inner surface of a rod pipe. In such projecting provision of the fishing line guides on the inner surface of the rod pipe, there is employed a method in which fishing line guide mother material is wound around a core metal after a thick tape having a thickness equal to or more than the height of the fishing line guides is wound around the core metal. PA0 (4) In view of the manufacturing method for providing the fishing line guides on the inner surface of the rod pipe, there arise problems that, when the fishing rod is flexed, stresses are centralized on the rod pipe main body side so that the rod pipe can be broken at such stress-centralized portion, and also that the above-mentioned fishing line guides are poor in durability. Further, even when the fishing line guides are provided, if the shapes and sizes of the fishing line contact portions of the fishing line guides are not set properly, then it is not possible to enhance the reduction effect of the fishing line resistance. PA0 (5) As means for providing fishing line guides, in Japanese Utility Model Publication No. 5-88259 of Heisei, there is disclosed an interline fishing rod in which a fishing line guide provided on and projected from the inner peripheral surface of a rod pipe main body layer is formed integrally with the rod pipe main body layer. PA0 (6) As noted above, in the interline fishing rod, in view of the fact that the fishing line is inserted and guided through the interior portion of the rod pipe, since there arises a basic problem that the resistance of the fishing line increases, there is provided an annular guide ring or a spiral-shaped fishing line guide in the interior portion of the rod pipe for receiving the fishing line, thereby preventing an increase in the resistance of the fishing line. Also, in the fishing rod with a fishing line guided outside the rod, there are provided on the outer periphery of the fishing rod a plurality of guide rings spaced apart from each other in the longitudinal direction of the fishing rod, and the fishing line is inserted and guided through the guide rings. PA0 (7) In an interline fishing rod, in order to prevent a fishing line from touching the inner surface of a rod pipe to thereby increase the resistance of the fishing line, it is quite common to provide a fishing line guide in the interior portion of the rod pipe. Such fishing line guide includes a ring-shaped fishing line guide, a spiral-shaped fishing line guide and the like. The spiral-shaped fishing line guide is used because it can be provided easily and at low costs.
However, an experiment conducted by the present applicants shows that, when a large number of fishing line guides such as the spiral-shaped fishing line guides are arranged, the shape disclosed in the above-mentioned patent publication is not preferred from the viewpoint of reducing the resistance of the fishing line in such a manner that the fishing line guides are prevented against wear in the special points thereof and thus the durability of the fishing line guides is also kept from being impaired.
However, when the thick tape is wound around the core metal, due to its thickness and the like, the thick tape is difficult to be in close contact with the core metal and is thus hard to be stabilized in its wound condition. Also, when the thick tape is removed later from the rod pipe after it is formed, the removing operation must be performed efficiently.
Conventionally, a rod pipe main body layer is generally formed thin in order to reduce the weight of the rod pipe. As described above, in the above-mentioned conventional fishing rod, the fishing line guide is formed integrally with such thin rod pipe main body layer, that is, the existence of the fishing line guide causes its peripheral portion to increase in rigidity. Therefore, when the fishing rod is flexed, stresses are centralized in the integrally formed fishing line guide peripheral portion of the rod pipe main body layer. Accordingly, when fish is caught and thus the fishing rod is flexed very greatly, there is a fear that the rod pipe can be broken due to such stress centralization.
In a fishing rod manufacturing method in which a spiral-shaped fishing line guide is integrally provided on and projected from the inner surface of a rod pipe, generally, a heat resisting tape having a thickness corresponding to the projection amount of the fishing line guide is wound around a core metal, fishing line guide forming mother material is wound in a clearance existing between the side edges of the tape wound, a prepreg for forming a rod pipe main body is then wound from above the fishing line guide forming mother material, and the above-mentioned components or the resultant assembly is then heated to thereby form a rod pipe.
However, if the size or shape of the tape clearance is deviated from a predetermined value, then the fishing line guide forming mother material cannot be wound correctly, or, when the components are heated, the resin of the rod pipe main body forming prepreg spreads into a gap between the tape clearance and fishing line guide forming mother material to thereby form burrs, so that the thus formed fishing line guide can damage the fishing line or can bring about an increase in the fishing line resistance. In consideration of a mold releasing property or the like, the above-mentioned heat resisting tape is generally composed of a synthetic resin tape which is formed of single material such as fluorine resin or the like and, therefore, the tape is rigid and thus is difficult to be wound around a portion which is small in diameter. On the other hand, if the tape is formed flexible, then the elongation percentage of the tape is also increased and, therefore, when the tape is wound with tension applied thereto, the section shape of the tape is deformed, which causes the tape clearance or the like to be deviated from the predetermined value.
Also, when the tape is removed after the rod pipe is formed, the tape can be cut during the tape removing operation, which makes it difficult to remove the remaining portions of the tape.
Further, from the viewpoint of the cost and weight thereof, the pitch of the spiral-shaped fishing line guide or the clearance between the annular guide rings must be set large. Or, when the inside diameter of a rod pipe is too small and thus it is difficult to provide a projecting fishing line guide on the inner surface of the rod pipe, instead of providing the projecting fishing line guide, slightly uneven portions or slight undulations are formed on the inner surface of the rod pipe and water repellent material or highly sliding material such as wax or the like is stored and held in the slight undulations, in order to reduce the resistance of the fishing line. That is, there is a need to manufacture easily and simply a fishing rod which can satisfy these requirements. I
Moreover, in the fishing rod with a fishing line guided outside the rod, if the clearance between a plurality of guide rings provided on the outer periphery of the rod pipe at such clearance from each other in the longitudinal direction thereof is too large, then there is a possibility that the fishing line can hang down and touch the surface of the rod pipe in such large clearance. Especially, if the rod pipe surface is wet with water, then there arises an inconvenience that the fishing line adheres to the wet rod pipe surface and thus the fishing line cannot be played out smoothly.
However, if a rod pipe including a spiral-shaped fishing line guide is flexed greatly due to a load applied thereto, then a fishing line is received substantially only by the local portion of the fishing line guide that exists at a position of a large flexure curvature. Therefore, it is not sufficient to simply devise the cross section shape of the spiral-shaped fishing line guide itself. If the shape of the cross section of the spiral-shaped fishing line guide extending in a direction at right angles to the longitudinal direction of the rod pipe is approximate to the shape of a ring-shaped fishing line guide, then the fishing line can be received in a proper condition and, therefore, such spiral-shaped fishing line guide is ideal as a fishing line guide. However, in this case, if the circumferential shape of such cross section is formed in a projecting shape, then the fishing line is easy to come out of the projectingly-shaped surface of the fishing line guide and, therefore, such fishing line guide is not suitable for a fishing line guide. Also, as in the spiral-shaped fishing line guide in which the shape of the cross section thereof is approximate to that of the ring-shaped fishing line guide, if the most part of the inner periphery of a rod pipe is almost covered by the spiral-shaped fishing line guide, similarly to a case in which a rod pipe is increased in thickness more than necessary, the rod pipe increases in weight, which is contrary to the reduction of the weight of a fishing rod. Further, if the reinforced area of a fishing line guide is collectively arranged only in the local portion of the inner periphery of the fishing line guide, then stress centralization is easy to occur there.